Cardiovascular Anatomv Understand the basic structure of the heart - how many ch
ID: 3512757 • Letter: C
Question
Cardiovascular Anatomv Understand the basic structure of the heart - how many chambers and what are they called; what are the main vessels that are connected to the heart either for inflow or outflow of blood; where are the valves and what are they called? Understand the basic functions of the heart what is the role of the left versus right side; which chamber pumps into which vessel; which vessels fill into which chamber; when are the valves open and when are they closed; why is the left ventricular muscle mass generally larger for a healthy person? What does it mean for blood pressure to be 120/80 mmHg? What is Ohm's law for fluids, and what does this mean in terms of the systemic circulation? What is cardiac output, and how does it compare for the left versus right side of the heart? hases of the Heart Remember that this is my favorite diagram, and with good reasorn What are the two main phases of the heart, and what are the sub-phases (e.g. isovolumetric contraction)? On this figure, you should be able to explain the interaction between the following: aortic and left ventricular pressure; left ventricular and left atrial pressure; pressures and left ventricular volume You should be comfortable with explaining- as we discussed in class the various phases of the heart, and what activities are occurring in the heart and vessels during those phasesExplanation / Answer
Cardiovascular Anatomy
Heart
The heart is a muscular cone-shaped organ about the size of a clenched fist of the same person. It is located in the upper body chest area between the lungs, and with its pointed end called the apex downwards, forwards, and pointing towards the left.
The main purpose of the heart is to pump blood around the body.
The basic structure of the heart
The heart is divided into separate right and left sections by the interventricular septum, or just the septum. Each of these right and left sections is also divided into upper and lower compartments known as atria and ventricles.
The four main chambers of the heart are:
1) Right Atrium
2) Right Ventricle
3) Left Atrium
4) Left Ventricle
Deoxygenated blood from the body is pumped through the right atrium and the right ventricle to the lungs, while oxygenated blood from the lungs is pumped through the left atrium and the left ventricle to the body.
Deoxygenated blood enters the right atrium from the superior vena cava and the inferior vena cava.
Deoxygenated blood leaves the right ventricle by pulmonary artery, which takes blood to the lungs via the right and left branches of the pulmonary artery.
Oxygenated blood enters the left atrium from the pulmonary veins.
These may be labeled as right pulmonary veins and left pulmonary veins.
Oxygenated blood leaves the left ventricle by ascending aorta, which takes blood to the body via its system of arteries, arterioles, and capillaries. Major arteries leading from the heart (via the ascending aorta) include the brachiocephalic artery, the left common carotid artery, and the left subclavian artery .This is just a few of the main arteries of the body.
It is essential that blood flows in the correct direction through the heart so the structure of the heart includes a series of valves.
Valves
1) The tricuspid valve separates the right atrium from the right ventricle.
2) The pulmonic / pulmonary valve separates the right ventricle from the pulmonary artery.
3) The mitral also known as the bicuspid valve separates the left atrium from the left ventricle.
4) The aortic valve separates the left ventricle from the ascending aorta.
TRICUSPID VALVE
i) Closes off the upper right chamber or atrium that holds blood coming in from the body.
II) Opens to allow blood to flow from the top right chamber to the lower right chamber or from right atrium to right ventricle.
III) Prevents the back flow of blood from the ventricle to the atrium when blood is pumped out of the ventricle.
PULMONARY VALVE
I) closes off the lower right chamber or right ventricle.
II) Opens to allow blood to be pumped from the heart to the lungs through the pulmonary artery where it will receive oxygen.
MITRAL VALVE
I) closes off the upper left chamber or left atrium collecting the oxygen-rich blood coming in from the lungs.
II) Opens to allow blood to pass from the upper left side to the lower left side or from the left atrium to the left ventricle.
AORTIC VALVE
I) closes off the lower left chamber that holds the oxygen-rich blood before it is pumped out to the body.
II) Opens to allow blood to leave the heart from the left ventricle to the aorta and on to the body.
Functions of Heart
1) Transports
Dissolved gases (e.g. oxygen, carbon dioxide)
Waste products of metabolism (e.g. water, urea)
Hormones
Enzymes
Nutrients (such as glucose, amino acids, micro-nutrients as vitamins & minerals, fatty acids, glycerol)
Plasma proteins (associated with defense, such as blood-clotting and anti-bodies)
Blood cells
2) Maintains Body Temperature
3) Controls pH
The pH of blood must remain in the range 6.8 to 7.4; otherwise it begins to damage cells.
4) Removes toxins from the body
The kidneys filter all of the blood in the body, 36 times every 24 hours. Toxins removed from the blood by the kidneys leave the body in the urine.
5) Regulation of Body Fluid Electrolytes
Excess salt is removed from the body in urine, which can contain around 10 g salts per day in the cases of people eating western diets that contain more salt than the body requires.
The main functions of the heart can be summarized as follows:
Right-Hand Side of the Heart
The right-hand side of the heart receives de-oxygenated blood from the body tissues from the upper- and lower-body via the superior vena cava and the inferior vena cava, respectively into the right atrium. This de-oxygenated blood passes through the tricuspid valve into the right ventricle. This blood is then pumped under higher pressure from the right ventricle to the lungs via the pulmonary artery.
Left-Hand Side of the Heart
The left-hand side of the heart receives oxygenated blood from the lungs through the pulmonary veins) into the left atrium. This oxygenated blood then passes through the bicuspid valve into the left ventricle. It is then pumped to the aorta under greater pressure this higher pressure ensures that the oxygenated blood leaving the heart via the aorta is effectively delivered to other parts of the body via the vascular system of blood vessels include. arteries, arterioles, and capillaries.
The pump action performed by the heart is achieved by a sequence of alternating contraction and relaxation of the heart muscle. In this context the term systole refers to the contraction part of the sequence and the term diastole to the relaxation part of the sequence. Hence, the systolic and "diastolic" pressures may be measured and recorded separately when monitoring blood pressure.
This process is directed by the nervous system, nerve impulses initiating each sequence. The whole series of actions that cause alternating contractions and relaxations may be summarized in five stages:
1) The vagus nerve stimulates the Sinoatrial node, the pacemaker of the heart.
The sinoatrial node is a tiny area of specialized cardiac muscle in the upper wall of the right atrium, near the vena cava . The fibers of the SAN contract rhythmically approx. 70 times each minute. After each of these contractions, the impulse is dispersed across the atrial cardiac muscle.
2) Simultaneous contraction of both the right and left atria. This movement of the cardiac muscle pushes blood from the atria into the ventricles via the tricuspid and bicuspid valves.
3) The contractions of the atria send impulses down the Purkinje fibers, which in turn stimulate the atrioventricular node (AVN). The atrioventricular node is a mass of modified cardiac muscle located in the lower/central part of the right atrium of the heart Purkinje Fibers and as the Bundle of His. This/these are a bundle of modified cardiac muscle fibers that transmit impulses from the atria, via the AVN, to the ventricles.
4) The action potential from the impulse transmitted down the Purkinje fibers reaches the right and left branches of the Purkinje fibers - as shown in the diagram on the right .This causes the...
5) ventricles to contract, which pushes blood upwards into the arteries that take the blood away from the heart (the pulmonary artery taking blood to the lungs, and the aorta taking blood to the body).
Systemic Circulation
1) Blood Pressure
When your heart beats, it pumps blood round your body to give it the energy and oxygen it needs. As the blood moves, it pushes against the sides of the blood vessels. The strength of this pushing is your blood pressure. If your blood pressure is too high, it puts extra strain on your arteries and your heart. This may lead to heart attacks and strokes
Systolic Blood Pressure Number Mean
When your heart beats, it squeezes and pushes blood through your arteries to the rest of your body. This force creates pressure on those blood vessels, and that's your systolic blood pressure.
A normal systolic pressure is below 120.
A reading of 120-129 is elevated.
130-139 is stage 1 high blood pressure also called hypertension.
140 or more is stage 2 hypertension.
180 or more is a hypertensive crisis.
Diastolic Blood Pressure Number Mean
The diastolic reading, or the bottom number, is the pressure in the arteries when the heart rests between beats. This is the time when the heart fills with blood and gets oxygen.
A normal Diastolic pressure is below 80.
A reading of 80-89 is elevated.
Right-Hand Side of the Heart
The right-hand side of the heart receives de-oxygenated blood from the body tissues from the upper- and lower-body via the superior vena cava and the inferior vena cava, respectively into the right atrium. This de-oxygenated blood passes through the tricuspid valve into the right ventricle. This blood is then pumped under higher pressure from the right ventricle to the lungs via the pulmonary artery.